> Paul Crowley <Paul@crowleyp.demon.co.uk> wrote in article> > > A female chimp with infant would find bipedal progression> > extremely difficult if not impossible.> > JW: Be careful Paul, I can feel feminist hackles rising. A male> could do this, but a determined and resourceful female could> not. Is that what you are saying?

Gerrit and I had a long exchange on this here about three months
ago. Chimps carry infants in the ventral position until they are
about 4 years old - especially on long journeys when the infant
gets tired. And infant-carrying is the prerogative of females.
While Gerrit demurred, I maintained that it would be almost
inconceivable that a chimp - female or male - would adopt a
bipedal posture while carrying a heavy infant.

My argument is that the first step towards bipedalism must
necessarily have been the putting down of the infant. I believe
that this probably occured when the females of one population
began to wade or swim through water in order to get food, or to
get to a food resource. A lot of evidence points to this, but
I'd be open to other explanations so long as they compel the
putting down of the infant.

> > The spines of knuckle-walking apes enter the skull towards the> > back, so they naturally look forward at all times.> > JW: They naturally look forward when their trunk is vertical. It> is not usually vertical when they are knuckle walking.

I have Goodall's "Through a Window" to hand. It has many pictures
of chimps knuckle-walking and clearly looking forward. It's their
normal way of getting about. If they could not easily see where
they were going, they would not have survived.